Liquid transfer device

ABSTRACT

A liquid transfer device to discharge viscosity liquid from vacuum vessel to atmosphere, particularly comprising an extruding shaft sequentially equipped with an introducing segment, a pressurizing segment, a counter-pressurizing segment, and a discharging segment. The counter-pressurizing segment is mainly provided to generate a sealing ring, thereby preventing air leakage resulting from outlet to the viscosity liquid source.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a liquid transfer device, particularly relates to a liquid transferring pump for liquids of high viscosity.

[0003] 2. Description of the Related Arts

[0004] Screw-pumps are generally used to transfer liquids of high viscosity such as thermoplastic materials, melted synthetic fibers, and others. Essentially, a screw pump is equipped with a rotary component with spiral vanes. The rotary component rotates relative to the pump body, and the liquid is suctioned into the pump from one aperture, extruded by the rotary component, and then expelled from the pump via another aperture.

[0005] Familiar forms of screw pumps include dual-screw, tri-screw, and single screw. For examples, dual-screw pumps are applied in U.S. Pat. No. 4,984,974, U.S. Pat. No. 5,080,845 and U.S. Pat. No. 5,308,562. For a pump having more than two screw shafts, it is characterized that the spiral vanes on each shaft must be precisely matched to each other. Theoretically, the transferring efficiency of the screw pump is in inverse proportion to the clearance between the shaft's vanes. However, for high-viscosity thermoplastic liquids, factors of thermo-expansion should be considered. Dimensions of the screw shafts and the vanes thereon are thus determined by the required propulsion force, the working temperature (differing from material to material), and the thermo-expansion coefficient of the screw shaft itself. Consequently, manufacture of multi-screw pumps tends to be complicated and expensive.

[0006] Single-screw pumps are applied in U.S. Pat. No. 4,104,009, U.S. Pat. No. 4,170,436, U.S. Pat. No. 4,211,506, U.S. Pat. No. 4,580,955, U.S. Pat. No. 4,772,177, U.S. Pat. No. 50,730,082, U.S. Pat. No. 5,195,631, U.S. Pat. No. 5,195,880, U.S. Pat. No. 5,395,225, U.S. Pat. No. 5,553,742 and U.S. Pat. No. 5,679,618. A conventional single-screw pump (not shown) is characterized by the driving manner of the screw shaft. Besides the spiral vanes thereon, the screw shaft of the single-screw pump has a twisted shape itself. In operation, within the transferring chamber of the pump body, the screw shaft executes a “revolution” around a central axis, and simultaneously executes a rotation around its own central axis. Correspondingly, the shape of the inner wall of the chamber is formed to fit the eccentrically rotating spiral vanes. Also, the shape of the pump and the driving mechanism for the screw shaft are complex, resulting in high fabrication costs and potential malfunctions.

[0007] A common problem in the operation of a screw pump is the leakage of air. The air neutralizes the vacuum in the transferring chamber, and enervates the extruding force exerted on the liquid. Many patents are provided for solving this problem. For example, JP06114915A provided a single-screw extruder for extruding melted fibers. In the extruder, a spiral shaft is comprised of a segment equipped with spiral threads at low pitches, and this segment may abate air leakage. The device is further equipped with a detecting device for air leakage. When air leakage is detected, a vacuum pump is started to maintain the vacuum of the extruder.

[0008] In addition, the sealing mechanisms, used to connect the screw shaft to the pump body, are easily permeated by the transferred materials. Accumulation of the materials can damage the sealing mechanisms. U.S. Pat. No. 4,447,061, for example, provides a method of enclosing the sealing mechanism with a fluid-tight manner, and reducing the pressure in the enclosed space by a vacuum apparatus to prevent leaking. U.S. Pat. No. 4,984,974 provides a vacuum pump comprising means for introducing inert gas into a working chamber in a pump casing, the inert gas is conducted towards at least the sealing associated with a bearing thereof, thereby preventing a deposition of a process gas handled by the vacuum pump from accumulating on components of the vacuum pump.

[0009] To solve the problems mentioned above, according to the prior arts, additional equipment or sensors are often required. The prior arts have not yet solved the problems of complexity and high-price.

SUMMARY OF THE INVENTION

[0010] The present invention is provided to effectively solve the problems mentioned above.

[0011] The first aspect of the present invention is a liquid transfer device, introducing a liquid into a chamber via an inlet thereof and discharging the liquid via an outlet thereof, the liquid transfer device comprising: a rotation actuator; and shaft, rotated by the rotation actuator.

[0012] The shaft comprising: an introducing segment, comprising a first spiral vane, provided to introduce the liquid from the inlet; a pressurizing segment adjacent to the introducing segment, comprising a second spiral vane that spirals in accordance with the first spiral vane, wherein the pitches of the second spiral vane reduce gradually along the shaft to pressurize the liquid; a first counter-pressurizing segment adjacent to the pressurizing segment, comprising a third spiral vane that spirals contrary to the first spiral vane, thereby pushing the liquid with a contrary pressure; and a discharging segment adjacent to the first counter-pressurizing segment, discharging the liquid via the outlet.

[0013] The contrary pressure surpasses the atmospheric pressure. The shaft is further comprised of discharging vanes on the discharging segment, pushing the liquid out through the outlet. Furthermore, the rotation actuator is a motor.

[0014] The second aspect of the present invention is a liquid transfer device, comprising: a main body, comprising a chamber, an inlet and an outlet to and from the chamber, and a menstruum inlet through which a menstruum is introduced to the chamber; a shaft disposed in the chamber, comprising an introducing segment near the inlet and a discharging segment near the outlet; a first pivot device equipped to the main body, pivoting one end of the shaft to the main body, wherein the end is adjacent to the discharging segment; a rotation actuator, coupling and rotating the shaft.

[0015] The shaft further comprising: a first spiral vane, mounted on the introducing segment, introducing a liquid from the inlet and pushing the liquid toward the discharging segment along the shaft; a pressurizing segment adjacent to the introducing segment, comprising a second spiral vane that spirals in accordance with the first spiral vane, with the pitch of the second spiral vane reducing gradually along the shaft, pressuring the liquid; a first counter-pressurizing segment disposed between the pressurizing segment and the discharging segment, comprising a third spiral vane that spirals contrary to the first spiral vane, thereby applying a contrary pressure; and a second counter-pressurizing segment disposed between the discharging segment and the first pivot device, comprising a fourth spiral vane that spirals contrary to the first spiral vane, thereby applying contrary pressure and preventing the liquid from permeating the first pivot device.

[0016] The contrary pressure surpasses the atmospheric pressure. The liquid is a liquid of high viscosity. Particularly, the liquid comprises melted thermoplastic materials. Furthermore, the liquid is a melt polymer.

[0017] The liquid transfer device of the present invention further comprising a casing that covers the main body and forms a containing space between the casing and the main body, wherein the casing is comprised of at least two apertures, through which a heat-transfer media is conducted to enter and exit the containing space.

[0018] The discharging segment is further comprised of discharging vanes on the discharging segment, pushing the liquid toward the outlet.

[0019] The liquid transfer device of the present invention further comprising a second pivot device equipped to the main body, whereby the shaft is pivoted to the main body with another end adjacent to the introducing segment. The shaft further comprises a third counter-pressurizing segment disposing between the introducing segment and the second pivot device, wherein the third counter-pressurizing segment is comprised of a fifth spiral vane that spirals in accordance with the first spiral vane, thereby applying pressure, and preventing the liquid from permeating the second pivot device.

[0020] Furthermore, the first and the second pivot device are sealing mechanisms, and the rotation actuator is a motor.

BRIEF DESCRIPTION OF DRAWINGS

[0021] The present invention can be fully understood from the following detailed description and preferred embodiment with reference to the accompanying drawings in which:

[0022]FIG. 1 shows a cross-section view of the liquid transfer device according to embodiment of the present invention.

[0023]FIG. 2 shows a perspective view of the liquid transfer device according to embodiment of the present invention.

DETAIL DESCRIPTION OF THE EMBODIMENT

[0024] As shown in FIG. 1, the embodiment according to the present invention is a liquid transfer device 100, which is adapted to transport liquids of high viscosity, for example thermoplastic material. The liquid transfer device comprises a main body 10, the main body is comprised of a chamber 11 and an inlet 12 and an outlet 13 that expose the chamber 11. A shaft 20 is disposed in the chamber 11. The shaft 20 is comprised of an introducing segment 21 near to the inlet 12 and a discharging segment 22 near to the outlet 13.

[0025] A first pivot device 30, preferably a sealing mechanism, is integrated in the main body 10, in which one end of the shaft 20 is pivotally anchored in the chamber 11, wherein the end is close to the discharging segment 22.

[0026] The present embodiment further comprises a rotation actuator 40, preferably a motor. The motor 40 is coupled to the shaft 20, rotating the shaft 20.

[0027] A detail description of the shaft 20 is listed below.

[0028] The shaft 20 is further comprised of multiple first spiral vanes 21 a, a pressurizing segment 23, a first counter-pressurizing segment 24, and a second counter-pressurizing segment 25. The first spiral vanes 21 a are attached to the introducing segment 21. The first spiral vanes 21 a are used to apply a drag force as the shaft 20 rotates, thereby introducing the liquid via the inlet 12.

[0029] The pressurizing segment 23 is adjacent to the introducing segment 21. The segment comprises plural second spiral vanes 23 a, which spiral around the orientation in accordance with the rotation of the first spiral vanes 21 a. Particularly, the pitch of the second spiral vanes reduces gradually along the shaft 20, generating an extruding pressure on the liquid.

[0030] The first counter-pressurizing segment 24 is disposed between the pressurizing segment 23 and the discharging segment 22. The first counter-pressurizing segment 24 comprises plural third spiral vanes 24 a, which spiral counter to the rotation of the first spiral vanes 21 a. With the third spiral vanes 24 a, a contrary pressure may be generated along the shaft 20. In an operation of the whole device 100, if the supply of the liquid is interrupted, the air outside will tend to invade the chamber 11 via the outlet 13. In this event, the function of the third spiral vanes 24 a will be brought into full play, and the contrary pressure will cause the transported liquid to generate a sealing ring to prevent air from outlet 13 from permeating the chamber 11, maintaining the vacuum of the chamber 11.

[0031] The second counter-pressurizing segment 25 is disposed between the discharging segment 22 and the first pivot device 30. The segment is equipped with plural fourth spiral vanes 25 a, which spiral counter to the rotation of the first spiral vanes 21 a. The segment is provided to generate contrary pressure, preventing the liquid from permeating the first pivot device 30 and damaging it.

[0032] To resist air leakage, the contrary pressure generated by the first counter-pressurizing segment 24 should surpass the atmospheric pressure in the periphery of the whole device 100. The numbers and dimensions of the third spiral vanes 24 a should be set according to these conditions.

[0033] Preferably, in FIG. 1 or 2, the shaft 20 is comprised of multiple discharging vanes 22 a on the discharging segment 22, conducting the liquid to the outlet 13.

[0034] Preferably, the present embodiment is equipped with a second pivot device 50, which is preferably another sealing mechanism. The second pivot device 50 is provided to pivotally associate another end of the shaft 20 in the chamber 11 to the main body 10. Wherein, the end associated with the second pivot device 50 is near to the introducing segment 21. Moreover, the shaft 20 is preferably disposed with a third counter-pressurizing segment 26 between the introducing segment 21 and the second pivot device 50. The third counter-pressurizing segment 26 comprises multiple fifth spiral vanes 26 a, which spiral around the same rotation of the first spiral vanes 21 a. The segment is mainly provided to prevent the liquid from permeating the second pivot device 50.

[0035] Additionally, the liquid transfer device 100 of the present embodiment is comprised of a casing 60, which covers the main body, and forms a containing space between the main body 10 and the casing 60. The casing is comprised of two apertures 61 and 62, through which a heat-transfer media for heating the liquid inside the chamber 11 may be conducted, and flowing through the containing space via the apertures 61 and 62.

[0036] Moreover, in FIG. 1, for cleaning counter pressure segment 25, the main body 10 is preferably comprised of a menstruum inlet 14, through which some proper menstruum could be introduced into the chamber 11.

[0037] According to the liquid transfer device of the present invention, the first counter-pressurizing segment 24 could prevent air leakage resulting from the interruption of the high-viscosity liquid source, and the vacuum in the working chamber is maintained. Furthermore, the second and third counter-pressurizing segment 25, 26 could prevent the liquid from permeating and damaging the sealing mechanisms. Additionally, the functions provided in the present invention are just approached by the dimensional and structural design of the components therein, and no additional power sources or mechanisms are needed.

[0038] The liquid transfer device of the present invention could be applied in many areas, such as simply liquid transferring or plastic injection processes.

[0039] While the invention has been described with reference to a preferred embodiment, the description is not intended to be constructed in a limiting sense. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as may fall within the scope of the invention defined by the following claims and their equivalents. 

What is claimed is:
 1. A liquid transfer device, introducing a liquid into a chamber via an inlet thereof and discharging the liquid via an outlet thereof, the liquid transfer device comprising: a rotation actuator; and a shaft, rotated by the rotation actuator, the shaft comprising: an introducing segment, comprising a first spiral vane, provided to introduce the liquid from the inlet; a pressurizing segment adjacent to the introducing segment, comprising a second spiral vane that spirals in accordance with the first spiral vane, wherein the pitches of the second spiral vane reduce gradually along the shaft for a pressurizing of the liquid; a first counter-pressurizing segment adjacent to the pressurizing segment, comprising a third spiral vane that spirals contrary to the first spiral vane, whereby pushing the liquid with a contrary pressure; and a discharging segment adjacent to the first counter-pressurizing segment, discharging the liquid via the outlet.
 2. The liquid transfer device of claim 1, wherein the contrary pressure surpasses the atmospheric pressure.
 3. The liquid transfer device of claim 1, wherein the shaft is further comprised of discharging vanes on the discharging segment, pushing the liquid out through the outlet.
 4. The liquid transfer device of claim 1, wherein the rotation actuator is a motor.
 5. A liquid transfer device, comprising: a main body, comprising a chamber, an inlet and an outlet into and out of the chamber, and a menstruum inlet though which a menstruum is introduced to the chamber; a shaft disposed in the chamber, comprising an introducing segment near the inlet and a discharging segment near the outlet; a first pivot device equipped to the main body, pivoting one end of the shaft to the main body, wherein the end is adjacent to the discharging segment; a rotation actuator, coupling and rotating the shaft; and the shaft further comprising: a first spiral vane, equipped to the introducing segment, introducing a liquid from the inlet and pushing the liquid toward the discharging segment along the shaft; a pressurizing segment adjacent to the introducing segment, comprising a second spiral vane that spirals in accordance with the first spiral vane, and the pitches of which reduce gradually along the shaft, thereby pressuring the liquid; a first counter-pressurizing segment disposed between the pressurizing segment and the discharging segment, comprising a third spiral vane that spirals contrary to the first spiral vane, thereby applying the liquid with a contrary pressure; and a second counter-pressurizing segment disposed between the discharging segment and the first pivot device, comprising a fourth spiral vane that spirals contrary to the first spiral vane, applying the liquid with a contrary pressure and preventing the liquid from permeating the first pivot device.
 6. The liquid transfer device of claim 5, wherein the contrary pressure surpasses the atmospheric pressure.
 7. The liquid transfer device of claim 5, wherein the liquid is a liquid of high viscosity.
 8. The liquid transfer device of claim 5, wherein the liquid comprises melted thermoplastic materials.
 9. The liquid transfer device of claim 5, wherein the liquid is a melted polymer.
 10. The liquid transfer device of claim 5, further comprising a casing that covers the main body and forms a containing space between the casing and the main body, wherein the casing is comprised of at least two apertures, through which a heat-transfer media is conducted to enter and exit the containing space.
 11. The liquid transfer device of claim 5, wherein the discharging segment is further comprised of discharging vanes on the discharging segment, whereby pushing the liquid toward the outlet.
 12. The liquid transfer device of claim 5, further comprising a second pivot device equipped to the main body, whereby the shaft is pivoted to the main body with another end adjacent to the introducing segment.
 13. The liquid transfer device of claim 12, wherein the shaft further comprises a third counter-pressurizing segment disposing between the introducing segment and the second pivot device, wherein the third counter-pressurizing segment is comprised of a fifth spiral vane that spirals in accordance with the first spiral vane, whereby applying a pressure that preventing the liquid from permeating into the second pivot device.
 14. The liquid transfer device of claim 13, wherein the first and the second pivot device are sealing mechanisms.
 15. The liquid transfer device of claim 5, wherein the rotation actuator is a motor. 